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→INVESTIGATION 3: OTHER COMMANDS THAT USE REGULAR EXPRESSIONS
# Press the letter <span style="color:blue;font-weight:bold;font-family:courier;">q</span> to exit the '''more''' command.<br><br>
#Let's learn how to perform a simple '''search and replace''' within the '''vi''' utility by using regular expressions.<br>Issue the following linux command to edit the '''textfile1.txt''' file:<br><span style="color:blue;font-weight:bold;font-family:courier;">vi textfile1.txt</span><br><br>Let's first perform a simple search within this text file.
# Type the following and press ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">/uli101</span><br><br>You should move to the first occurrence of uli101.<br><br>Let's search for the '''uli101''' pattern, but replace it in capitals (i.e '''ULI101''').<br><br>. In vi, in order to perform and command, you need to go into last line mode, and then issue a command to apply to the entire text file, followed by a regular expression to search for and a regular expression to replace (i.e. /search/replace/).<br><br># Type the following and press ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">:%s/uli101/ULI101</span><br><br>You should have noticed that the first occurrence of uli101 has been changed to ULI101.<br><br>
# Navigate throughout the text file to see if the other occurrences have been replaced.<br><br>You should notice they haven't for the other two occurrences. In order to replace for ALL occurrences, you need to add the letter g (meaning "global") at the end of the last forward slash (e.g /search/replace/g).<br><br>
Making certain that you are command mode in vi, type the following and press ENTER:<br><span style="color:blue;font-weight:bold;font-family:courier;">:%s/uli101/ULI101/g</span><br><br>
